About 77% of known human disease genes have a recognizable match in the genetic code of fruit flies, and 50% of fly protein sequences have mammalian analogues.

That’s why fruit flies, known to scientists as Drosophila melanogaster, are commonplace in genetic research labs. They can be good substitutes for people. They reproduce quickly, so that many generations can be studied in a short time, and their genome has been completely mapped. Drosophila is being used as a genetic model for several human diseases including Parkinson’s and Huntington’s.
They’re about to become genetic models for astronauts. Bhattacharya said:

We are sending fruit flies to the International Space Station. They will orbit Earth alongside astronauts, helping us explore the effects of long-term space flight on human beings.

The flies will be living in a habitat developed at Ames called the “Fruit Fly Lab.” Inside, they will lead the hurried lives of fruit flies – living, dying, reproducing, and experiencing the same space radiation and microgravity as their human counterparts. Cameras will record the behavior and appearance of these miniature astronauts; and at intervals some of them will be frozen and returned to Earth for analysis.

Bhattacharya said:

The Fruit Fly Lab will allow us to look into a variety of questions such as the effect of space flight on aging, cardiovascular fitness, sleep, stress and much more.